/*******************************************************************************
 * Copyright (c) 1991, 2016 IBM Corp. and others
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution and
 * is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following
 * Secondary Licenses when the conditions for such availability set
 * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
 * General Public License, version 2 with the GNU Classpath
 * Exception [1] and GNU General Public License, version 2 with the
 * OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] http://openjdk.java.net/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
 *******************************************************************************/

#include "gcutils.h"

#include <string.h>

#include "EnvironmentBase.hpp"
#include "GCExtensionsBase.hpp"
#include "VerboseManager.hpp"

#include "VerboseHandlerOutput.hpp"
#include "VerboseHandlerOutputStandard.hpp"
#include "VerboseWriter.hpp"
#include "VerboseWriterChain.hpp"
#include "VerboseWriterHook.hpp"
#include "VerboseWriterFileLogging.hpp"
#include "VerboseWriterFileLoggingBuffered.hpp"
#include "VerboseWriterFileLoggingSynchronous.hpp"
#include "VerboseWriterStreamOutput.hpp"

/**
 * Create a new MM_VerboseManager instance.
 * @return Pointer to the new MM_VerboseManager.
 */
MM_VerboseManager *
MM_VerboseManager::newInstance(MM_EnvironmentBase *env, OMR_VM* vm)
{
	MM_GCExtensionsBase* extensions = MM_GCExtensionsBase::getExtensions(vm);
	
	MM_VerboseManager *verboseManager = (MM_VerboseManager *)extensions->getForge()->allocate(sizeof(MM_VerboseManager), OMR::GC::AllocationCategory::FIXED, OMR_GET_CALLSITE());
	if (verboseManager) {
		new(verboseManager) MM_VerboseManager(vm);
		if(!verboseManager->initialize(env)) {
			verboseManager->kill(env);
			verboseManager = NULL;
		}
	}
	return verboseManager;
}

/**
 * Kill the MM_VerboseManager instance.
 * Tears down the related structures and frees any storage.
 */
void
MM_VerboseManager::kill(MM_EnvironmentBase *env)
{
	tearDown(env);

	MM_GCExtensionsBase* extensions = MM_GCExtensionsBase::getExtensions(env->getOmrVM());
	extensions->getForge()->free(this);
}

/**
 * Initializes the MM_VerboseManager instance.
 */
bool
MM_VerboseManager::initialize(MM_EnvironmentBase *env)
{
	OMRPORT_ACCESS_FROM_OMRPORT(env->getPortLibrary());
	MM_GCExtensionsBase *extensions = MM_GCExtensionsBase::getExtensions(env->getOmrVM());
	_mmPrivateHooks = J9_HOOK_INTERFACE(extensions->privateHookInterface);
	_omrHooks = J9_HOOK_INTERFACE(extensions->omrHookInterface);

	_writerChain = MM_VerboseWriterChain::newInstance(env);
	if (NULL == _writerChain) {
		return false;
	}
	
	if(NULL == (_verboseHandlerOutput = createVerboseHandlerOutputObject(env))) {
		return false;
	}

	_lastOutputTime = omrtime_hires_clock();
	
	return true;
}

/**
 * Tear down the structures managed by the MM_VerboseManager.
 * Tears down the event stream and outut agents.
 */
void
MM_VerboseManager::tearDown(MM_EnvironmentBase *env)
{
	disableVerboseGC();
	
	if(NULL != _verboseHandlerOutput) {
		_verboseHandlerOutput->kill(env);
		_verboseHandlerOutput = NULL;
	}

	_writerChain->kill(env);
}

MM_VerboseHandlerOutput *
MM_VerboseManager::createVerboseHandlerOutputObject(MM_EnvironmentBase *env)
{
	MM_VerboseHandlerOutput *handler = NULL;
	MM_GCExtensionsBase *extensions = env->getExtensions();

	if (extensions->isStandardGC()) {
#if defined(OMR_GC_MODRON_STANDARD)
		handler = MM_VerboseHandlerOutputStandard::newInstance(env, this);
#endif /* defined(OMR_GC_MODRON_STANDARD) */
	} else {
		handler = MM_VerboseHandlerOutput::newInstance(env, this);
	}

	return handler;
}

void
MM_VerboseManager::closeStreams(MM_EnvironmentBase *env)
{
	MM_VerboseWriter *writer = _writerChain->getFirstWriter();
	while(NULL != writer) {
		writer->closeStream(env);
		writer = writer->getNextWriter();
	}
}

void
MM_VerboseManager::enableVerboseGC()
{
	if (!_hooksAttached) {
		_verboseHandlerOutput->enableVerbose();
		_hooksAttached = true;
	}
}

void
MM_VerboseManager::disableVerboseGC()
{
	if (_hooksAttached) {
		_verboseHandlerOutput->disableVerbose();
		_hooksAttached = false;
	}
}

/**
 * Finds an agent of a given type in the event chain.
 * @param type Indicates the type of agent to return.
 * @return Pointer to an agent of the specified type.
 */
MM_VerboseWriter *
MM_VerboseManager::findWriterInChain(WriterType type)
{
	MM_VerboseWriter *writer = _writerChain->getFirstWriter();

	while (NULL != writer){
		if (type == writer->getType()){
			return writer;
		}
		writer = writer->getNextWriter();
	}

	return NULL;
}

/**
 * Counts the number of output agents currently enabled.
 * @return the number of current output agents.
 */
uintptr_t
MM_VerboseManager::countActiveOutputHandlers()
{
	MM_VerboseWriter *writer = _writerChain->getFirstWriter();
	uintptr_t count = 0;

	while(NULL != writer) {
		if(writer->isActive()) {
			count += 1;
		}
		writer = writer->getNextWriter();
	}

	return count;
}

/**
 * Walks the output agent chain disabling the agents.
 */
void
MM_VerboseManager::disableWriters()
{
	MM_VerboseWriter *writer = _writerChain->getFirstWriter();

	while(NULL != writer) {
		writer->isActive(false);
		writer = writer->getNextWriter();
	}
}

WriterType
MM_VerboseManager::parseWriterType(MM_EnvironmentBase *env, char *filename, uintptr_t fileCount, uintptr_t iterations)
{
	MM_GCExtensionsBase* extensions = env->getExtensions();

	if(NULL == filename) {
		return VERBOSE_WRITER_STANDARD_STREAM;
	}

	if(!strcmp(filename, "stderr") || !strcmp(filename, "stdout")) {
		return VERBOSE_WRITER_STANDARD_STREAM;
	}

#if defined(OMR_RAS_TDF_TRACE)
	if(!strcmp(filename, "trace")) {
		return VERBOSE_WRITER_TRACE;
	}
#endif /* OMR_RAS_TDF_TRACE */

	if(!strcmp(filename, "hook")) {
		return VERBOSE_WRITER_HOOK;
	}

	if (extensions->bufferedLogging) {
		return VERBOSE_WRITER_FILE_LOGGING_BUFFERED;
	}

	return VERBOSE_WRITER_FILE_LOGGING_SYNCHRONOUS;
}

/**
 * Configures verbosegc according to the parameters passed.
 * @param filename The name of the file or output stream to log to.
 * @param fileCount The number of files to log to.
 * @param iterations The number of gc cycles to log to each file.
 * @return true on success, false on failure
 */
bool
MM_VerboseManager::configureVerboseGC(OMR_VM *omrVM, char *filename, uintptr_t fileCount, uintptr_t iterations)
{
	MM_EnvironmentBase env(omrVM);

	MM_VerboseWriter *writer = NULL;

	disableWriters();

	WriterType type = parseWriterType(&env, filename, fileCount, iterations);

	writer = findWriterInChain(type);

	if (NULL != writer) {
		writer->reconfigure(&env, filename, fileCount, iterations);
	} else {

		writer = createWriter(&env, type, filename, fileCount, iterations);

		if(NULL == writer) {
			return false;
		}

		_writerChain->addWriter(writer);
	}

	writer->isActive(true);

	return true;
}

MM_VerboseWriter *
MM_VerboseManager::createWriter(MM_EnvironmentBase *env, WriterType type, char *filename, uintptr_t fileCount, uintptr_t iterations)
{
	MM_VerboseWriter *writer = NULL;
	switch(type) {
	case VERBOSE_WRITER_STANDARD_STREAM:
		writer = MM_VerboseWriterStreamOutput::newInstance(env, filename);
		break;
	case VERBOSE_WRITER_HOOK:
		writer = MM_VerboseWriterHook::newInstance(env);
		break;
	case VERBOSE_WRITER_FILE_LOGGING_SYNCHRONOUS:
		writer = MM_VerboseWriterFileLoggingSynchronous::newInstance(env, this, filename, fileCount, iterations);
		if (NULL == writer) {
			writer = findWriterInChain(VERBOSE_WRITER_STANDARD_STREAM);
			if (NULL != writer) {
				writer->isActive(true);
				return writer;
			}
			/* if we failed to create a file stream and there is no stderr stream try to create a stderr stream */
			writer = MM_VerboseWriterStreamOutput::newInstance(env, NULL);
		}
		break;
	case VERBOSE_WRITER_FILE_LOGGING_BUFFERED:
		writer = MM_VerboseWriterFileLoggingBuffered::newInstance(env, this, filename, fileCount, iterations);
		if (NULL == writer) {
			writer = findWriterInChain(VERBOSE_WRITER_STANDARD_STREAM);
			if (NULL != writer) {
				writer->isActive(true);
				return writer;
			}
			/* if we failed to create a file stream and there is no stderr stream try to create a stderr stream */
			writer = MM_VerboseWriterStreamOutput::newInstance(env, NULL);
		}
		break;

	default:
		return NULL;
	}

	return writer;
}
